Toughness of high‐density polyethylene in plane‐strain fracture
Bibliographic record
Abstract
Abstract Under uniaxial tension, high‐density polyethylene (HDPE) often fractures in a ductile manner. The fracture involves extensive necking that is known to occur in the plane‐stress condition. However, for large‐scale HDPE products like polyethylene pipe, crack can grow rapidly in a brittle manner. This type of fracture is known to be in the plane‐strain condition, which has much lower toughness than that in the plane‐stress condition. In this study, we extended the concept of essential work of fracture (EWF) to the plane‐strain condition and evaluated the fracture toughness of extruded HDPE plate. The results show that the specific work of fracture in the plane‐strain condition is also a linear function of the specimen ligament length. Therefore, the corresponding EWF value can be determined in a similar manner, that is, through linear extrapolation to zero ligament length. For HDPE, the study found that the plane‐strain toughness is about one order of magnitude smaller than the plane‐stress counterpart. Interestingly, the plane‐strain EWF value is very close to the estimated toughness of pressurized polyethylene pipe, which was reported in the literature, predicted using numerical simulation based on data from the standard small‐scale steady‐state (S4) test. POLYM. ENG. SCI. 46:1428–1432, 2006. © 2006 Society of Plastics Engineers.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".